This disclosure relates to an image reader and an image forming apparatus, and more specifically to a technology in which a direction of a document is determined.
Some of recent multifunction peripherals combining a plurality of functions such as a copy function, a printer function, a scanner function, and a facsimile function have an automatic document direction detection function of detecting a direction of a document upon scanning.
Suggested is, for example, a technology in which, upon reading of a plurality of documents in a bundle, a direction of each document is automatically determined and, based on results of the determination, rotation processing is performed on image data of each document when necessary to thereby align the directions of document image data. Further suggested is a technology in which, when a direction of a document cannot be determined on one surface, the direction of the document is determined on another surface. Moreover, another technology is suggested in which, upon reading of a plurality of documents in a bundle, only a direction of the first document (1-page document) is determined and, based on results of the determination, the same rotation processing as that performed on image data of the first document is performed on the second document and beyond to thereby align directions of the documents.
Then also known is a technology in which a direction of characters included in a document image is detected by using a character recognition (typically called OCR) function and a direction of the document is detected based on the detected direction of the characters.
Also suggested is a technology in which image concentration distribution is obtained through a character recognition function, based on the concentration distribution, a concentration distribution region of characters is converted into black and other regions are converted into white to thereby narrow down a target of character recognition to the characters whose image is formed in black and thereby more improve accuracy in the character recognition. With this technology, when subjected to reading, concentration of a dropout color image in particular turns low and thus this image is converted into white and excluded from the target of character recognition. Moreover, upon detection of, for example, a ruled line, processing of excluding the ruled line from the target of character recognition is performed, thus improving the accuracy in the character recognition also in this regard.